Technical Field
This invention relates to a control device for a vehicle including a torque converter including a lock-up mechanism, and a variable compression ratio mechanism arranged to vary a compression ratio.
Related Art
For example, a patent document 1 discloses an art configured to decrease a compression ratio at an engagement of a lock-up clutch in a driving region in which the lock-up clutch is engaged in cooperation with the compression ratio to bring the lock-up mechanism to a lock-up ON state, and thereby to effectively use effect of the compression ratio variation to improve fuel economy of the vehicle.
However, in general, a response at the engagement of the lock-up clutch is better than a response of the variable compression ratio mechanism at the variation of the compression ratio. Moreover, the torque variation of the internal combustion engine during one cycle becomes greater as the compression ratio becomes higher. That is, in the patent document 1, the lock-up clutch is engaged before the compression ratio becomes low. Accordingly, the large vehicle vibration may be generated due to the torque variation of the internal combustion engine.
Patent Document 1: Japanese Patent No. 5146598